1. Field of the Invention
The present invention relates to hydraulic circuits for excavators or other heavy equipment, and, more specifically to hydraulic circuits which recover and store energy in a compact and efficient manner.
2. Description of the Related Art
It is well known in the art to use hydraulic circuits to provide power to various devices of excavator or other heavy equipment vehicles. These devices can include propulsion, steering, braking, and the manipulation of various implements. Typically, an engine provides power to a shaft, which in turn provides power to various components in the hydraulic circuit.
Hydraulic circuits are composed of many components, including cylinders, pumps, motors, several types of valves, and accumulators. These components are placed in series and/or parallel to each other in order to direct hydraulic fluid in a particular direction and to provide specific functions. Depending upon the setting of directional valves, for example, various circuits can be created by isolating and/or including different components.
During use, and depending upon the operation desired, hydraulic circuits consume various quantities of energy from the engine and from its own components. There is often a tradeoff, for example, when using several implements on the same circuit: while one implement may be used at peak efficiency, other implements may as a result of the circuit design operate at less than peak efficiency. In addition, the hydraulic circuit, when in operation, puts a load on the engine and therefore requires the engine to consume more fuel in order to keep the hydraulic system operating.
What is therefore needed in the art is a hydraulic circuit which is highly efficient, reduces engine power requirements, and may reduce the quantity of system components needed.